diff options
Diffstat (limited to 'src/runtime/pprof/pprof.go')
| -rw-r--r-- | src/runtime/pprof/pprof.go | 51 |
1 files changed, 16 insertions, 35 deletions
diff --git a/src/runtime/pprof/pprof.go b/src/runtime/pprof/pprof.go index 20ccb51b00..70544acde1 100644 --- a/src/runtime/pprof/pprof.go +++ b/src/runtime/pprof/pprof.go @@ -74,12 +74,13 @@ import ( "bytes" "fmt" "io" - "os" "runtime" + "runtime/pprof/internal/protopprof" "sort" "strings" "sync" "text/tabwriter" + "time" ) // BUG(rsc): Profiles are only as good as the kernel support used to generate them. @@ -670,49 +671,29 @@ func StartCPUProfile(w io.Writer) error { } func profileWriter(w io.Writer) { + startTime := time.Now() + // This will buffer the entire profile into buf and then + // translate it into a profile.Profile structure. This will + // create two copies of all the data in the profile in memory. + // TODO(matloob): Convert each chunk of the proto output and + // stream it out instead of converting the entire profile. + var buf bytes.Buffer for { data := runtime.CPUProfile() if data == nil { break } - w.Write(data) + buf.Write(data) } - // We are emitting the legacy profiling format, which permits - // a memory map following the CPU samples. The memory map is - // simply a copy of the GNU/Linux /proc/self/maps file. The - // profiler uses the memory map to map PC values in shared - // libraries to a shared library in the filesystem, in order - // to report the correct function and, if the shared library - // has debug info, file/line. This is particularly useful for - // PIE (position independent executables) as on ELF systems a - // PIE is simply an executable shared library. - // - // Because the profiling format expects the memory map in - // GNU/Linux format, we only do this on GNU/Linux for now. To - // add support for profiling PIE on other ELF-based systems, - // it may be necessary to map the system-specific mapping - // information to the GNU/Linux format. For a reasonably - // portable C++ version, see the FillProcSelfMaps function in - // https://github.com/gperftools/gperftools/blob/master/src/base/sysinfo.cc - // - // The code that parses this mapping for the pprof tool is - // ParseMemoryMap in cmd/internal/pprof/legacy_profile.go, but - // don't change that code, as similar code exists in other - // (non-Go) pprof readers. Change this code so that that code works. - // - // We ignore errors reading or copying the memory map; the - // profile is likely usable without it, and we have no good way - // to report errors. - if runtime.GOOS == "linux" { - f, err := os.Open("/proc/self/maps") - if err == nil { - io.WriteString(w, "\nMAPPED_LIBRARIES:\n") - io.Copy(w, f) - f.Close() - } + profile, err := protopprof.TranslateCPUProfile(buf.Bytes(), startTime) + if err != nil { + // The runtime should never produce an invalid or truncated profile. + // It drops records that can't fit into its log buffers. + panic(fmt.Errorf("could not translate binary profile to proto format: %v", err)) } + profile.Write(w) cpu.done <- true } |